The present invention relates to retention arrangements and more particularly to retention arrangements in the form of a split ring to retain association between components.
It will be understood that particularly in relation to engines where there are rotating shafts it is important to retain association between coverplate seals and other components such as a retaining disc for blades.
Referring to FIG. 1, a gas turbine engine is generally indicated at 10 and comprises, in axial flow series, an air intake 11, a propulsive fan 12, an intermediate pressure compressor 13, a high pressure compressor 14, combustion equipment 15, a high pressure turbine 16, an intermediate pressure turbine 17, a low pressure turbine 18 and an exhaust nozzle 19.
The gas turbine engine 10 works in a conventional manner so that air entering the intake 11 is accelerated by the fan 12 which produce two air flows: a first air flow into the intermediate pressure compressor 13 and a second air flow which provides propulsive thrust. The intermediate pressure compressor compresses the air flow directed into it before delivering that air to the high pressure compressor 14 where further compression takes place.
The compressed air exhausted from the high pressure compressor 14 is directed into the combustion equipment 15 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive, the high, intermediate and low pressure turbines 16, 17 and 18 before being exhausted through the nozzle 19 to provide additional propulsive thrust. The high, intermediate and low pressure turbine 16, 17 and 18 respectively drive the high and intermediate pressure compressors 14 and 13, and the fan 12 by suitable interconnecting shafts.
FIG. 2 illustrates a typical prior retention arrangement for a coverplate 21 secured to a disc 22 through a retention ring 23. As can be seen, the retention ring 23 acts between a disc retention feature 24 and an end of the coverplate 21.
The coverplate 21 is fitted or removed by collapsing the ring 23 into a groove 25 between the feature 24 and the remainder of the disc 22. It will be understood that the retention ring 23 is generally split so that the split or gap is closed when the ring 23 is collapsed into the groove 25 and allowed to open or expand into the position depicted in FIG. 2 in use and forced into greater expansion in order to be lifted over the feature 24 for ring removal. It will be understood in order to provide retention there is a thrust rolling off-set 26 between the coverplate 21 and the feature 24 and a CF rolling off-set 27 between the ring 23 and parts of the coverplate 21.